The present invention is related to a soldering gun having a finger actuated soldering feed apparatus and particularly to such a soldering gun of a pistol-type construction.
Electrical components are often connected into circuit by soldering of the electrical terminals to other components, wires, conductors, and the like. Various forms of soldering devices have been developed. A particularly useful soldering apparatus for production line construction of electrical circuits includes a pistol-type soldering gun having a finger actuated solder feeding apparatus or mechanism. A pistol-type soldering gun, for example as shown in U.S. Pat. No. 4,199,096 which issued Apr. 22, 1980, provides a satisfactory type of construction. In such pistol-type apparatus, a depending handle is integrated into the back portion of a solder wire feed barrel. A heated soldering member is secured projecting from the barrel and terminates in the outer end in a pointed heated tip. A suitable electrical heating unit in the member is coupled to the tip to raise the temperature of the tip for heating and melting of the solder wire. The heating unit is connected in the circuit through a lead mechanism extending rearwardly through the barrel and generally out through the handle structure. A suitable on/off control switch may be provided for selected melting of the solder. A coil of the solder wire is mounted directly to the gun and fed through the barrel in alignment with the tip for feeding the end of the wire into engagement with the tip end thereby providing for melting of the end of the solder wire and depositing of the melted solder accurately onto a circuit assembly. A trigger in the handle of the gun actuates a feeding mechanism for controlled feeding of the wire onto the tip.
Various feeding mechanisms have been suggested in the prior art. The above patent for example illustrates a pivoted and spring-load feedarm coupled to trigger wherein the depression of the trigger moves the spring-load feeded arm forwardly. The arm engages the wire and moves the wire forwardly through the barrel. Upon release of the trigger, the spring loading of the pivoted arms allows the arm to slide rearwardly over the wire into a reset position for the subsequent feed. The length of wire fed with each trigger actuation can be preset through an adjustable mechanism varying the length of the stroke.
Alternate types of soldering gun devices are shown in the other patent art wherein a pencil type soldering gun terminates in a heated tip with means for feeding of a solder wire through the pencil unit into engagement with the heated tip. For example, U.S. Pat. No. 4,507,545 which issued on Mar. 26, 1985 discloses a pencil-type soldering gun having a finger actuated wheel for driving of the soldering wire forwardly through the pencil unit. The finger actuated wheel is coupled to a knurled wheel engaging the wire such that rotation of the wheels propels the soldering wire through the apparatus. U.S. Pat. No. 1,925,656 which issued Sept. 5, 1933 also discloses a pencil type unit with finger actuated input wheel operating a feed wheel with the solder wire moving between the feed wheel and a spring loaded back wheel.
A solder gun with a similar feed wheel connected to a trigger is available from Hakko Metal Industries, Ltd. of Ozaka, Japan. In the structure, a ratchet wheel is coupled to a finger actuated trigger for rotating the ratchet wheel. The solder wire is clamped between the ratchet wheel and an opposing pressure roll which is loaded by a fixed hair-pin spring to continuously hold the pressure roll into biased engagement with the wheel and/or the solder wire. It is difficult to remove the cartridge as a result of the continued pressurized engagement of the solder wire by the wheel feed mechanism. Other solder feed units are shown in the following U.S. Patents:
______________________________________ U.S. Pat. No. Issue Date Inventor ______________________________________ 2,014,728 08-27-1934 Forney 2,058,634 10-27-1936 Rusk 2,280,879 04-28-1942 Anderson 2,444,267 06-29-1948 Pereira 3,211,355 10-12-1965 Zoltai 3,232,509 02-01-1966 Newton 3,252,645 05-24-1966 Zoltai 3,521,804 07-28-1970 Jacobs 4,199,096 04-22-1980 Keefe et al 4,247,137 01-27-1981 St. Clair 4,330,075 05-18-1982 Rosen 4,411,379 10-25-1983 Gravel ______________________________________
Notwithstanding the various devices which have been proposed including those which are commercially available, there is a continuing demand and need for a simpler, effective and reliable soldering gun apparatus of the pistol type construction, preferably including a coil wire cartridge releasably mounted to the gun for efficient production line soldering.